The helicopter has many advantages for moving different types of loads from place to place and is particularly effective in retrieving and moving loads in remote or inaccessible areas. One problem encountered in airlifting loads using this aircraft with a depending hoist line is the connecting of the lower end of the hoist line to the load. In the past the most common practice has been to use a grappling hook or some other type of hook on the end of a hoist line to hook into the load or a cable attached to the load. In most cases ground personnel is used to make certain there is a reliable connection between the hoist line and the load.
In many aerial load pickup situations it is also highly desirable to be able to readily release the load from the hoist line without ground personnel. An example of the requirements of this type of coupling is disclosed in my copending application Ser. No. 103,348, entitled "Apparatus and Methods for Line Stringing", wherein a needle-like structure is carried by the hoist line suspended from a helicopter to thread the line through tower supported line-holding structure and particularly a tower with line holding structure that has no side access such as for stringing the center line.
Accordingly, it is an object of the present invention to provide a novel and improved load pickup coupling device between a hoist line and a load that may be applied generally to load pickups from an aircraft, the methods related thereto, and more particularly to the stringing of a sock line associated with stringing electric power lines.